This proposal provides plans for the execution of the normal tasks of a Coordinating Center to assess the feasibility of conducting a full- scale, randomized, multi-center clinical trial which will attempt to evaluate a stepped-care approach to slowing progression of renal disease in black, hypertensive patients with evidence of chronic renal disease. Three types of antihypertensive agents are proposed for use as the primary step in each of three treatment arms: diuretics, converting enzyme inhibitors, and calcium channel blockers. The study will also evaluate whether the degree of blood pressure control achieved is important in reducing loss of renal function. The planning phase for this study will occupy the first 12 months of the funding period. The first three months will be used to organize cooperative meetings among the investigators. The purpose of these meetings will be to define end points, variables to be collected and time intervals for their collection, rules for the clinical stepped-care protocol, and to address the details of the clinical protocol to be used. A written protocol reflecting this agreement will be produced. Following the protocol development, it will be necessary to produce a written manual of operations and to develop draft version of the data collection instruments. When a working version has been produced, the distributed data entry system will be designed. Prior to the testing of the study procedures, we will hold training sessions for the staff of the clinical centers in the clinical procedures, use of data collection forms, recruitment and follow-up procedures, procedures for documentation and handling of adverse reactions, and the data entry system. This will include a careful review of the manual of operations and the coding to be used for the data collection, on an item by item basis. When this is completed, it will be necessary to test all study procedures including clinic procedures, data collection forms and the distributed data entry system. In Phase II, patients will be recruited at the clinical centers. Centers will be followed closely so that problems can be discovered and resolved as quickly as possible. On-site monitoring of the clinics will be done prior to the start of recruitment and at four month intervals thereafter. Bimonthly conference telephone calls will be scheduled to discuss and resolve problems. Routine statistical analyses will be performed to look for clinic to clinic differences, inconsistencies within clinics, inconsistencies within records for individual patients, evidence of coding problems, etc. High noncompliance rates, rates of adverse reactions and drop-outs will also be monitored. Throughout the recruitment and follow-up phase, the Steering Committee will be promptly informed on the nature and frequency of any major problems so that it may take appropriate action. After the closing of the data files for the pilot study, final statistical analyses will be performed and written reports of these analyses will be generated by the Coordinating Center. The results will be incorporated into the collaboratively written reports by the Steering Committee, recommending either the continuation and expansion of the study or discontinuation of the trial.